Spark plug



June 10, 1924."

L. T. QUIGLEY SPARK PLUG Filed Dec. 13, 1920 Patented June 10, 1924.

UNITED STATES PATENT orrica.

LEO T. QUIGTJEY, OE WASHINGTON, DISTRICT OF COLUMBIA. ASSIGNOR 0F ONE-HALF T0 ISAAC SAMSTAG, OF WASHINGTON, DISTRICT OF COLUMBIA.

SPARK PLUG.

Application filed December 13, 1920. Serial No. 436289.

T 0 all whom it may concern:

Be it known that I. Lno T. QUIGLEY, a citizen of the United States, residing at \Vashington, in the District of Columbia, have invented new and useful, Improvements inSpark Plugs, of which the following is a specification.

This invention relates to improvements in spark plugs.

The primary object of the invention is to provide a construction whereby the accumulation of carbon deposits on the portions of the plug exposed to the interior of the engine cylinder is prevented by mounting one of the electrodes in the plug in such a manner that it may vibrate and also have a swinging movement whereby the carbon tending to cling thereon or to the adjacent parts of the plug will be maintained in a loose condition suitable for being conveyed out of the engine cylinder as a part of the exhaust gases.

In order that the continued operation of the plug may not be interfered with, means are also provided to limit this swinging or rocking motion of one of the electrodes so that the gap between the electrodes may not become so great as to prevent the spark from jumping between them.

Another object of my invention is to provide a spark plug with an electrode which may be easily assembled or replaced by another should such latter action become desirable or necessary.

The invention is herein more fully set forth and particularlv pointed out-in the claims.

In the accompanying drawings Fig. 1 is a longitudinal section through the casing of the spark plug as constructed in accordance with the preferred form of my invention.

Fi 2-is asection on the line 22 of Fig. 1 100 ing in the direction of the arrows.

Fig. 3 is a section on the line 3-3 of Fig. 1 looking in the direction of the arrows.

Referring to the drawings the numeral 10 designates the shell or casing of' the spark plug which is provided as usual with the external threads 11 at its lower end for engaging corresponding threads in the cylinder head of the engine and internal threads 12 at its upper end for engaging the corresponding threads of a retaining nut or bushing 13.. The porcelain insulator 14 i is also constructed in the usual manner having a shoulder 15 adapted to engage the shoulder 16 formed in the casing 10 and also having the depending skirt portion 17 projecting downwardly into the reduced cylindrical stem portion 24 of the casing. The electrode 18 is centrally embedded in the porcelain insulator and extends axially therethrough and through the skirt portion 17 until its lower terminal 19 projects beyond the end of the insulator into proximity to the other electrode 20.

The electrode 20 is preferably of substantially U-shape having the loop portion arranged substantially horizontal and disposed the proper distance from the terminal 19 of the positive electrode. The arms of the U-shaped electrode 20, shown herein as extending substantially vertically upward, are designated by the reference numerals 211. These vertical arms 21 are located in recesses or grooves 23 formed in the stem 24 of the casing, and these grooves extend nearly the full length of the cylindrical stem 24 and communicate with and terminate in radial depressions 25 which are slightly larger in diameter than the wire composin electrode 20. These oppositely arranged epressions 25 are adapted to receive the bent over ends 26 of the vertical arms 21. The relative diameter of these radial depressions 25 and the bent terminals 26 is such as to provide a good contact betweenthe electrode and the casing 10 but permit the electrode 20 to have a swinging or rocking motion. Tn order to aid the assembling of the electrode 20 to the casing and to promote good electrical.

contact between this electrode and the casing, the electrode should be made of resilient material so that the same when in proper positionwill snap into the depressions 26 owing to its inherent elasticity. Accordingly the ends 26-will abut against the bases of the depressions and thereby form firm electrical connections.

Tn operation-the central electrode 18 be-. ing connected to the external circuit indicated by the wire 27 and said wire becoming energized through the ignition system of the internal combustion engine, it is apparent that a spark will jump from the terminal 19 to the electrode 20. During the continued operation of the engine the vibrations set up will be sufiicient to provide a rocking motion of the electrode 20 about its pivots 2%,

are

' and this rocking motion in connection with the vibrations of the wire will tend to shake off carbon deposits from the electrode and also loosen any carbon which may have been deposited in the recesses 23 or on the exterior of the skirt portion 17. The recesses 23 are of such width as to limit the rocking motion of the U-shaped .electrode so that the same may not swing out of operative relation to the terminal 19 of the central electrode.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A plug for a high tension jump spark consisting of a metallic casing, an insulator a fixed and a movable electrode, said movable electrode being swingably supported by said casing on an axis positioned above the lower end of the fixed electrode.

2. A spark plug having a casing, an insulator, a fixed and a movable electrode, said movable electrode being U-shaped and pivotally mounted in said casing at substantially diametricall opposite points.

3. A spar plug comprising a casing, an

I insulator having an electrode fixed therein,

means for retaining said insulator in the easing, said casing being provided interiorly with a pair of opposite recesses terminating in radial de ressions, and a U-shaped electrode of sma ler diameter than the width of said recesses having vertically extending arms located in said recesses and bent over terminals pivotally mounted in said depressions whereby said U-shaped electrode may have a limited swin ing movement relatively to the fixed electro e.

4; In a spark plu having a casing provided with shallow e ressions on the inner surface thereof, a U-s aped electrode of resilient material having its ends bent angularly to enga e within said depressions whereby the elasticity of the material maintains said ends in firm contact with that portion of the casing forming the bases of the depressions.

In testimony whereof I have hereunto set my hand in presence of two subscribing wit- CHAS. S. Hxm, JAMEsL. Nomus. 

